Recycling of used products for reclamation of raw materials has become a way of life. Specifically, recycling of aluminum cans for reclamation of the aluminum is now commonplace.
Typically, a consumer saves a plurality of containers and brings these containers to a mobile or permanent recycling facility, where the containers are turned over to an employee of the recycling company who weighs or counts the containers and pays the consumer for the containers at a prestated rate. Unfortunately, such a system is labor intensive, requiring at least one operator to be at each facility whenever it is open.
One possible solution to the labor problem is to replace many of the manned stations with automated facilities. This, however, results in other problems.
If the ideal were reached, i.e., a customer places only aluminum cans into such a "reverse vending" machine, such a machine would be simple. All that would be necessary would be a means for weighing or counting the cans, a payout apparatus linked to the weighing or counting means and a means for storing the cans collected. However, such an ideal is never realized.
First, all beverage containers are not aluminum. Thus, a reverse vending machine must be capable of distinguishing steel from aluminum, so that no payment is made for steel cans.
While the placing of steel cans in a reverse vending machine designed to accept aluminum cans could be inadvertent on the part of the consumer, other deliberate acts must also be overcome by such a machine. It is not unknown for unscrupulous consumers to place bottles, rocks, sticks and other debris into reverse vending machines. Thus, the machine must be able to separate aluminum cans from this debris, handle the debris without damage to the machine and pay only for the aluminum cans. Additionally, other consumers, looking to cheat the machine, will place sand, rocks, water, and other materials into aluminum cans, hoping to be paid for the weight of the filled can. Or, a customer, not knowing the damage that a relatively large solid block of aluminum can do to a can crusher, may place portions of aluminum engine blocks, baseball bats and other massive aluminum materials into the reverse vending machine. Thus, in order to protect itself, as well as to avoid payment for weighted cans, the machine must be capable of discriminating between aluminum bodies based upon their weight.
Several means are known in the prior art for collecting aluminum containers. U.S. Pat. No. 4,179,018 uses air and magnetics as a means of isolating aluminum cans from mixed trash. U.S. Pat. No. 4,062,767 uses a linear induction motor (LIM) to accomplish this result. Yet, each of these systems has shortcomings associated therewith. Thus, the air classification system has trouble discriminating between various weights and shapes of cans, sometimes paying for somewhat overweight cans and sometimes not paying for acceptable material. The known LIM systems do not significantly control the mixed trash input to the linear induction motor so that proper control of overweight materials, as well as complete collection of properly weighted cans, is accomplished.
Another deficiency in many of the known reverse vending machines is the necessity, due to the layout and material flow of these machines, for a separate storage for steel cans which are inadvertently collected by the system. Since this storage area is typically small with respect to the storage area for aluminum cans, and since overflow of this small area requires frequent servicing of the machine, such a system either significantly increases servicing costs or significantly increases the size of the machine to provide adequate steel can storage.
Other problems which may arise in the operation of a reverse vending machine include overloading of a can crusher due to a high density of flattened cans or axially crushed cans, commonly known as "hockey pucks", and conveying mechanisms for the input to the machine being incapable of accepting the very last portions of input to the system.
It is thus a primary objective of the present invention to provide a reverse vending machine which is capable of discriminating between various weights of aluminum products received, such that overweight materials are not paid for and assure that acceptable materials are reliably paid for. It is also an objective of the present invention to eliminate the necessity for a separate steel storage facility. It is also a primary objective of the present invention to provide a reverse vending machine which includes means for preventing overloading of crushing means within the mechanism when high density aluminum is received. It is also a primary objective of the present invention to provide apparatus for insuring that all material received by the mechanism is processed by the system.